Inverter controlled generator set

An engine driven inverter controlled generator set comprising:

• a power supply unit that uses a generator driven by an engine as a power supply to output a DC voltage;
• an inverter device that converts the output voltage of said power supply unit into an AC voltage;
• and
• an engine rotational speed control unit that controls a rotational speed of said engine so as to be kept at a target rotational speed suitable for a load applied to said inverter device,
• wherein said engine rotational speed control unit is comprised so as to feedback control the rotational speed of said engine so as to bring a deviation between the rotational speed of said engine and the target rotational speed to zero when the load above a set value being applied to said inverter device is detected, and stepwise reduce said rotational speed by a predetermined range of reduction at fixed time intervals to reduce said rotational speed toward the target rotational speed when no load above the set value being applied to said inverter device is detected.